Machine for inserting weights in piano keys



Dec. 1924- 1,517,601

s. SYLVESTER MACHINE FOR INSERTING WEIGHTS IN PIANO KEYS Filed June 6, 1922 l I 19 29 F 15 1 INVENTOR \fi maursylvezer M Ll ' ATTORNEY Patented Dec. 2, 1924.

PATENT OFFICE.

SEYMOUR SYLVESTER, 0F BROOKLYN, NEW YORK.

MACHINE FOR INSERTING- WEIGHTS IN PIANO KEYS.

Application filed June 6, 1922.

T 0 all whom it may concern:

Be it known that I, SEYMOUR SYLVESTE-R, a citizen of the United States, residing at Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements in Machines for Inserting Vveights in Piano Keys, of which the following is a specification.

My invention relates to an improved ma chine for inserting weights in piano keys for the purpose of balancing the latter, and comprises certain principles which I believe to be fundamentally new in this art.

In Patent No. 1,383,497, granted July 5, 1921, I disclose a machine adapted to bal ance a piano key, drill an opening therein at a predetermined point and then insert a weight in the opening to permanently fix the balance of the key, and my present invention is designed to provide a novel machine for inserting the weight in the key opening.

It has been found that, in some cases, pellets inserted in the piano keys in the manner described in my prior patent, had a tendency to work loose. This was due to several causes, but primarily to the deformation of the seat for the pellets. By means of my present invention I entirely overcome this defect by providing a most effective interengagement of the pellet and key so that no amount of vibrating, warping or expansion of the key will permit the pellet to become released.

Stated in general terms, my invention consists in inserting a pellet, by rotary movement, into a preformed opening in the piano key, the pellet by preference being threaded and the preformed opening in the key being smooth walled.

The invention is illustratively exemplified in the accompanying drawings, wherein Fig. 1 is an elevational view of a pellet having its side wall threaded; Fig. 2 is a perspective view of a piano key with a pellet about to be inserted therein; Fig. 3 is a substantially vertical sectional view of an apparatus whereby my present method may be carried into practice.

In carrying my invention into practice I first place the key on a balancing device of some sort and by manipulation ascertain the precise point at which the key balances, and at this point drill a transverse opening through the key. I then insert the weight or pellet by first aligning the latter with the Serial No. 566,351.

opening drilled in the key and thereafter imparting a rotary movement to the pellet by means of a revolving driver. The latter operation will result in the thread of the pellet being brought into contact with the edge of the drilled opening whereupon the thread will bite into the preferably smooth wall of the opening and cut a thread throughout its length. Thus interengaged, the pellet may not be removed from the key without reversing the above operation.

Referring, now, to the drawing, Fig. 1. shows a pellet 10 comprising a cylindrical member provided with a continuous peripheral spiral thread 11. The opposite ends of the pellet are grooved at 12 to receive the end of the revolving tool. It has been found in practice that these pellets may be most economically made by the process of die castmg which lends itself well to the more or less soft weighty metal used in the manufacture of piano key weights.

In Fig. 2, I have shown a piano key 13 having an opening 14 drilled therein to receive the pellet 10 which is in position to be rotated into the opening.

In Fig. 3, an apparatus is illustrated, which is designed to automatically feed a pellet from a hopper and then by means of a revolving tool insert the weight into the preformed opening in the key, and which consists of a balancing device generally indicated at 15 and described in my earlier Patent No. 1,383,497, granted July 5, 1921. The parts of the structure comprise a base 16 having a slidably mounted carriag 17 movable transversely thereof. Opposed clamping jaws 18 are slidably mounted in guideways provided in the upper surface of the carriage 17 and are adapted to be moved against the opposite sides of the key 13 to hold the latter in position during the weighting operation. The balance member 19 is supported between the inner faces of the jaws 18 and receives the key 13 longitudinally thereof.

Thebase 16 is provided with a longitudinally disposed groove which receives a slide member 20 having a drill standard 21 and a tool standard 22 at opposite ends. Movement is imparted to the slide member by a lever 23 pivoted to the tool standard 22. Mounted in and reciprocable with the tool standard 22 is an automatically operated tool driver 24 which consists of a spirally fluted spindle 25 having an engaging end 26 to fit the grooves 12 in the ends of the pellets 10. The tool driver 24: projects axially of the slide member and is adapted to move through an opening 27 in the bottom portion of a hopper 28 and into the space between the upper and lower sections of the jaw 18. Suitable lugs 29 are carried by the wall of the opening 27 to engage the grooves of the spindle so that axial movement of the tool driver through the opening will cause the spindle to rotate. Movable with the tool driver 24 is a drill 30 mounted in a chuck 31 rotatably supported in the drill standard 21. The hopper 28 comprises an upright hollow chute 32 to receive the pellets which are fed to the opening 27 and thereafter projected forward by the driver 24 to engage with the key 13. Simultaneously with the axial movement of the driver 24 there will be a rotary movement of the latter, which movement will cause the engaging end 26 to register with the groove 12 in the end of the pellet and impart a similar rotary movement to the pellet, and, as the latter enters the opening 14 in the key 13, continued rotary movement will screw the weight 10 through the key. lVith the weight thus interengaged with the inner wall of the opening 14, all possible chance of the weight becoming released from the key from vibrating, warping or expansion of either member will be entirely overcome.

I claim:

A key weight insertingapparatus for the purpose specified. comprising a reciprocable member provided with a drill and a revolving tool driver at opposite ends thereof. means for supporting; a piano key between the said drill and tool driver and a hopper for feeding weights into the path of the revolving driver to insert by rotary movement a weight into an opening in the key made by the said drill.

In testimony whereof I afiix my signature.

SEYMOUR SYLVESTER. 

